A sharp expansion of the market for portable electronic equipment (e.g. PDAs and mobile phones) and downsizing of these apparatuses have resulted in demands for greater portability, i.e., smaller, thinner models with higher impact resistance, for disk drive apparatuses which act as data storage means for mobile digital equipment. A range of methods have been proposed to disk drive apparatuses with the aim of achieving improved impact resistance.
One example of a conventional disk drive apparatus employing a Flying-type head or flying head in a magnetic recording and reproducing apparatus, such as a hard disk drive apparatus, is described below with reference to the drawings.
FIG. 6 shows the configuration of the conventional magnetic recording and reproducing apparatus. In FIG. 6, head support assembly 108 is configured with suspension 102 with relatively low rigidity, spring portion 103, and supporting arm 104 with relatively high rigidity. Slider 101, on which a magnetic head (not illustrated) is installed, is disposed on the bottom face of one end of suspension 102.
Magnetic recording medium 107 is designed to rotate around spindle motor 109. During recording and playback by the magnetic recording and reproducing apparatus, the magnetic head installed on slider 101 fly from magnetic recording medium 107 to a predetermined distance by the levitation force of airflow generated on slider 101 created by the rotation of magnetic recording medium 107 and the force of head support assembly 108 applied to slider 101 toward magnetic recording medium 107. Voice coil 106 provided on supporting arm 104 rotates head support assembly 108 about bearing 105, during recording and playback, so as to position the magnetic head installed on slider 101 over the required track on magnetic recording medium 107 for recording and playback.
The magnetic recording and reproducing apparatus shown in FIG. 6 is a magnetic recording and reproducing apparatus adopting a system generally called the contact-start-stop system (CSS system). When magnetic recording medium 107 is stationary, the magnetic head is held in contact with magnetic recording medium 107. During recording and playback, however, the magnetic head on slider 101 fly from magnetic recording medium 107. In this CSS system, magnetic recording medium 107 is divided into zone A which is a data zone and zone B to where the magnetic head is moved when rotation stops. To stop the rotation of magnetic recording medium 107, the magnetic head is first moved to zone B while still flying, after which the rotation of magnetic recording medium 107 is slowed down. This reduces airflow between magnetic recording medium 107 and slider 101, resulting in reducing the Positive force or flying force. Finally, the magnetic head contacts magnetic recording medium 107 and stops. However, in some cases, when the magnetic head is stopped, the magnetic head adheres to magnetic recording medium 107. This results in mechanical and magnetic damage to recording medium 107 when restarting. To prevent this adhesion problem, the surface of zone B is made rougher than that of zone A on magnetic recording medium 107 in apparatuses employing the CSS system.
The load-unload system (L/UL system) is another system for supporting the head. FIG. 7 is a perspective view of the magnetic recording and reproducing apparatus employing the L/UL system. In FIG. 7, head support assembly 108 has a similar configuration to head support assembly 108 in the CSS system shown in FIG. 6. However, head support assembly 108 rotates about bearing 105 while the magnetic recording and reproducing apparatus is stopped so that head support assembly 108 is moved outside of magnetic recording medium 107. Magnetic head holder 110 is provided at the outside of magnetic recording medium 107, and protrusion 111 provided at the tip of suspension 102 is slid up onto a tapered portion of this magnetic head holder 110 so as to hold slider 101 and the magnetic head away from magnetic recording medium 107.
The configuration of the conventional head support assembly employed in these conventional magnetic recording and reproducing apparatuses and its operation are described next with reference to FIG. 8. FIG. 8 is a perspective view of a key part of the conventional head support assembly. The magnetic head (not illustrated) is installed on slider 101 provided on the bottom face of one end of low-rigidity suspension 102 in a way such that the magnetic head faces the magnetic recording medium (not illustrated). The other end of this suspension 102 is bent to act as spring portion 103. This spring portion 103 is connected to supporting arm 104. In the CSS system, slider 101 contacts the magnetic recording medium when the rotation of the magnetic recording medium is stopped, and the force is applied to slider 101 toward the magnetic recording medium by the reaction force of spring portion 103 against the magnetic recording medium.
The head support assembly of the magnetic recording and reproducing apparatus needs to have a certain degree of flexibility to apply a predetermined load on the slider toward the magnetic recording medium to make the slider trace the up-and-down movements of the surface of the magnetic recording medium. If the suspension is configured with a thin plate to give flexibility to the head support assembly, unstable phenomena such as vibration by bending or torsion occurs in the head support assembly. This is because such suspension has low rigidity and low resonance frequency that become apparent when positioning the head support assembly or moving the head to a standby position.
Accordingly, the following disadvantage is found in adopting the L/UL system with the above suspension structure. L/UL operation becomes unstable due to vibration of the suspension because the guide is provided at the tip of the low-rigidity suspension and this guide is slid up a tapered ramp. To prevent torsion of the suspension, the guide needs to be provided on the axis of symmetry of the suspension. This results in loss of design flexibility. In addition, downsizing of the disk drive apparatus becomes difficult because the L/UL mechanism is provided at the tip of the head supporting arm.
In the CSS system, on the other hand, the pressing force on the slider toward the surface of the magnetic recording medium while the rotation of the magnetic recording medium is stopped is primarily determined by the spring constant of the suspension. Accordingly, the surface roughness of the magnetic recording medium needs to be changed to prevent adhesion of the slider and magnetic recording medium. This is an impediment to the efficient use of the surface of magnetic recording medium, particularly when the size is reduced.
The present invention solves the above disadvantages of the prior art and aims to offer a disk drive apparatus having a head support assembly with high impact resistance that ensures stable L/UL operation or CSS operation.